*,
*:before,
*:after {
    box-sizing: border-box;
    margin    : 0;
    padding   : 0;
}
h1{
    font-size: 1em;
    padding: 0.5em;
    border-bottom: 1px solid #eee;
    color:cornflowerblue;
}
.container {
    display    : flex;
    flex-flow  : row nowrap;
    height     : 100vh;
    align-items: stretch;

    .ctrl {
        border-right: 1px solid #eee;
        flex        : 10px 1 1;
    }

    .prev {
        flex: 10px 2 1;
    }
}